Browse by author
Lookup NU author(s): Emeritus Professor Roger Francis
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Objectives To identify participants’ characteristics that influence the anti-fracture efficacy of vitamin D or vitamin D plus calcium with respect to any fracture, hip fracture, and clinical vertebral fracture and to assess the influence of dosing regimens and co-administration of calcium. Design Individual patient data analysis using pooled data from randomised trials. Data sources Seven major randomised trials of vitamin D with calcium or vitamin D alone, yielding a total of 68 517 participants (mean age 69.9 years, range 47-107 years, 14.7% men). Study selection Studies included were randomised studies with at least one intervention arm in which vitamin D was given, fracture as an outcome, and at least 1000 participants. Data synthesis Logistic regression analysis was used to identify significant interaction terms, followed by Cox’s proportional hazards models incorporating age, sex, fracture history, and hormone therapy and bisphosphonate use. Results Trials using vitamin D with calcium showed a reduced overall risk of fracture (hazard ratio 0.92, 95% confidence interval 0.86 to 0.99, P=0.025) and hip fracture (all studies: 0.84, 0.70 to 1.01, P=0.07; studies using 10 µg of vitamin D given with calcium: 0.74, 0.60 to 0.91, P=0.005). For vitamin D alone in daily doses of 10 µg or 20 µg, no significant effects were found. No interaction was found between fracture history and treatment response, nor any interaction with age, sex, or hormone replacement therapy. Conclusion This individual patient data analysis indicates that vitamin D given alone in doses of 10-20 µg is not effective in preventing fractures. By contrast, calcium and vitamin D given together reduce hip fractures and total fractures, and probably vertebral fractures, irrespective of age, sex, or previous fractures.
Author(s): Abrahamsen B, Masud T, Avenell A, Anderson F, Meyer HE, Cooper C, Smith H, La Croix AZ, Torgerson D, Johansen A, Jackson R, Rejnmark L, Wactawski Wende J, Brixen K, Mosekilde L, Robbins JA, Francis RM
Publication type: Article
Publication status: Published
Journal: British Medical Journal
Year: 2010
Volume: 340
Print publication date: 12/01/2010
Date deposited: 08/06/2010
ISSN (print): 0959-535X
ISSN (electronic): 1756-1833
Publisher: BMJ Group
URL: http://dx.doi.org/10.1136/bmj.b5463
DOI: 10.1136/bmj.b5463
Notes: See correction https://doi.org/10.1136/bmj.d5245 The authors of this research paper—the DIPART (vitamin D Individual Patient Analysis of Randomized Trials) Group—have become aware of a coding error relating to treatment allocation in one of the studies (the Porthouse study) included in their pooled analysis (BMJ 2010;340:b5463, doi:10.1136/bmj.b5463). This error affects the data relating to studies of vitamin D plus calcium reported in table 2 and figure 4. The authors have recalculated their data to take account of the error. They state that in table 2 the hazard ratios (and confidence intervals) shown in the “vitamin D 20 µg plus calcium” column should be 0.99 (0.84 to 1.19) for any fracture, 1.19 (0.81 to 1.75) for hip fracture, and 0.99 (0.49 to 2.04) for vertebral fracture [not 0.95 (0.80 to 1.14), 1.30 (0.88 to 1.92), 0.97 (0.48 to 1.98) respectively, as was published]. In figure 4, the hazard ratio for hip fracture in CaD [calcium and vitamin D] trials should be 0.83 (0.69-0.99) [not 0.84 (0.70 to 1.01) as published], which is now statistically significant, and the hazard ratio for all trials should be 0.96 (0.85-1.09) [not 0.97 (0.86 to 1.10)]. The authors state that the error led to a modest underestimation in their paper of the reduction in hip fracture risk for vitamin D supplements given with calcium, saying that “the results have been strengthened slightly by correcting this error and the reduction in hip fracture risk is now statistically significant.” After correction, the absolute hip fracture risk reduction remained at 0.4% for participants aged over 70 and 0.2% in participants with previous fractures, but the numbers needed to treat (NNT) are now 250 and 524 (not 255 and 548). The NNT for all fractures was correct as reported. For more information on this, see the authors’ Rapid Response (www.bmj.com/content/340/bmj.b5463.full/reply#bmj_el_268507).
Altmetrics provided by Altmetric
